This study seeks to further evaluate electroencephalographic and clinical responses to EEG feedback training in poorly controlled seizure disorder patients. Eighty-one patients with mixed partial (psychomotor) and generalized (tonic-clonic) seizures will be studied in a design providing for quantitative analysis of EEG and seizure incidence changes resulting from contingent vs. noncontingent EEG feedback training. Contingent training will provide reward for patterns of central cortical EEG frequency distribution which represent a normalization of documented EEG abnormalities. Noncontigent training will be based on EEG data recorded from a "yoked" contingent training subject. A third group of patients will receive no training during the same period and will then be entered into one of the two other groups. Baseline sleep and waking EEG samples will be computer analyzed for the derivation of central cortical EEG power-spectral profiles. Changes in these profiles and in seizure incidence, as measured by seizure logs and, in some patients, extended video and telemetered EEG monitoring, will be evaluated statistically within individuals and between groups. Additionally, a battery of performance and memory tests will be applied before and after training in order to evaluate the effect of EEG training on these parameters as well.